FFmpeg
Data Structures | Macros | Functions | Variables
vf_readeia608.c File Reference

Filter for reading closed captioning data (EIA-608). More...

#include <string.h>
#include "libavutil/internal.h"
#include "libavutil/opt.h"
#include "libavutil/pixdesc.h"
#include "libavutil/timestamp.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "video.h"

Go to the source code of this file.

Data Structures

struct  LineItem
 
struct  CodeItem
 
struct  ReadEIA608Context
 

Macros

#define LAG   25
 
#define CLOCK_BITSIZE_MIN   0.2f
 
#define CLOCK_BITSIZE_MAX   1.5f
 
#define SYNC_BITSIZE_MIN   12.f
 
#define SYNC_BITSIZE_MAX   15.f
 
#define OFFSET(x)   offsetof(ReadEIA608Context, x)
 
#define FLAGS   AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 

Functions

 AVFILTER_DEFINE_CLASS (readeia608)
 
static int query_formats (AVFilterContext *ctx)
 
static int config_input (AVFilterLink *inlink)
 
static void build_histogram (ReadEIA608Context *s, const LineItem *line, int len)
 
static void find_black_and_white (ReadEIA608Context *s)
 
static float meanf (const LineItem *line, int len)
 
static float stddevf (const LineItem *line, int len)
 
static void thresholding (ReadEIA608Context *s, LineItem *line, int lag, float threshold, float influence, int len)
 
static int periods (const LineItem *line, CodeItem *code, int len)
 
static void dump_code (AVFilterContext *ctx, int len, int item)
 
static void extract_line (AVFilterContext *ctx, AVFrame *in, int w, int nb_line)
 
static int filter_frame (AVFilterLink *inlink, AVFrame *in)
 
static av_cold void uninit (AVFilterContext *ctx)
 

Variables

static const AVOption readeia608_options []
 
static const AVFilterPad readeia608_inputs []
 
static const AVFilterPad readeia608_outputs []
 
AVFilter ff_vf_readeia608
 

Detailed Description

Filter for reading closed captioning data (EIA-608).

See also https://en.wikipedia.org/wiki/EIA-608

Definition in file vf_readeia608.c.

Macro Definition Documentation

#define LAG   25

Definition at line 39 of file vf_readeia608.c.

Referenced by build_histogram(), config_input(), extract_line(), and periods().

#define CLOCK_BITSIZE_MIN   0.2f

Definition at line 40 of file vf_readeia608.c.

Referenced by extract_line().

#define CLOCK_BITSIZE_MAX   1.5f

Definition at line 41 of file vf_readeia608.c.

Referenced by extract_line().

#define SYNC_BITSIZE_MIN   12.f

Definition at line 42 of file vf_readeia608.c.

Referenced by extract_line().

#define SYNC_BITSIZE_MAX   15.f

Definition at line 43 of file vf_readeia608.c.

Referenced by extract_line().

#define OFFSET (   x)    offsetof(ReadEIA608Context, x)

Definition at line 76 of file vf_readeia608.c.

Definition at line 77 of file vf_readeia608.c.

Function Documentation

AVFILTER_DEFINE_CLASS ( readeia608  )
static int query_formats ( AVFilterContext ctx)
static

Definition at line 90 of file vf_readeia608.c.

static int config_input ( AVFilterLink inlink)
static

Definition at line 108 of file vf_readeia608.c.

static void build_histogram ( ReadEIA608Context s,
const LineItem line,
int  len 
)
static

Definition at line 132 of file vf_readeia608.c.

Referenced by extract_line().

static void find_black_and_white ( ReadEIA608Context s)
static

Definition at line 140 of file vf_readeia608.c.

Referenced by extract_line().

static float meanf ( const LineItem line,
int  len 
)
static

Definition at line 182 of file vf_readeia608.c.

Referenced by stddevf(), and thresholding().

static float stddevf ( const LineItem line,
int  len 
)
static

Definition at line 194 of file vf_readeia608.c.

Referenced by thresholding().

static void thresholding ( ReadEIA608Context s,
LineItem line,
int  lag,
float  threshold,
float  influence,
int  len 
)
static

Definition at line 205 of file vf_readeia608.c.

Referenced by extract_line().

static int periods ( const LineItem line,
CodeItem code,
int  len 
)
static

Definition at line 244 of file vf_readeia608.c.

Referenced by extract_line().

static void dump_code ( AVFilterContext ctx,
int  len,
int  item 
)
static

Definition at line 267 of file vf_readeia608.c.

Referenced by extract_line().

static void extract_line ( AVFilterContext ctx,
AVFrame in,
int  w,
int  nb_line 
)
static

Definition at line 278 of file vf_readeia608.c.

Referenced by filter_frame().

static int filter_frame ( AVFilterLink inlink,
AVFrame in 
)
static

Definition at line 393 of file vf_readeia608.c.

static av_cold void uninit ( AVFilterContext ctx)
static

Definition at line 407 of file vf_readeia608.c.

Variable Documentation

const AVOption readeia608_options[]
static
Initial value:
= {
{ "scan_min", "set from which line to scan for codes", OFFSET(start), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
{ "scan_max", "set to which line to scan for codes", OFFSET(end), AV_OPT_TYPE_INT, {.i64=29}, 0, INT_MAX, FLAGS },
{ "spw", "set ratio of width reserved for sync code detection", OFFSET(spw), AV_OPT_TYPE_FLOAT, {.dbl=.27}, 0.1, 0.7, FLAGS },
{ "chp", "check and apply parity bit", OFFSET(chp), AV_OPT_TYPE_BOOL, {.i64= 0}, 0, 1, FLAGS },
{ "lp", "lowpass line prior to processing", OFFSET(lp), AV_OPT_TYPE_BOOL, {.i64= 1}, 0, 1, FLAGS },
{ NULL }
}
#define NULL
Definition: coverity.c:32
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
#define FLAGS
Definition: vf_readeia608.c:77
#define OFFSET(x)
Definition: vf_readeia608.c:76

Definition at line 79 of file vf_readeia608.c.

const AVFilterPad readeia608_inputs[]
static
Initial value:
= {
{
.name = "default",
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
}
#define NULL
Definition: coverity.c:32
static int config_input(AVFilterLink *inlink)
static int filter_frame(AVFilterLink *inlink, AVFrame *in)

Definition at line 415 of file vf_readeia608.c.

const AVFilterPad readeia608_outputs[]
static
Initial value:
= {
{
.name = "default",
},
{ NULL }
}
#define NULL
Definition: coverity.c:32

Definition at line 425 of file vf_readeia608.c.

AVFilter ff_vf_readeia608
Initial value:
= {
.name = "readeia608",
.description = NULL_IF_CONFIG_SMALL("Read EIA-608 Closed Caption codes from input video and write them to frame metadata."),
.priv_size = sizeof(ReadEIA608Context),
.priv_class = &readeia608_class,
}
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:125
static av_cold void uninit(AVFilterContext *ctx)
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
static const AVFilterPad readeia608_outputs[]
static const AVFilterPad readeia608_inputs[]
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
#define flags(name, subs,...)
Definition: cbs_av1.c:564
static int query_formats(AVFilterContext *ctx)
Definition: vf_readeia608.c:90

Definition at line 433 of file vf_readeia608.c.